Hip revision arthroplasty for severe acetabular defects using custom 3D-printed porous titanium implants: Minimum 2-year follow-up

Abstract

Purpose

was to evaluate the outcomes of custom 3D-printed trabecular titanium implants for acetabular revision total hip arthroplasty (rTHA) in patients with severe acetabular defects (Paprosky type 2 or 3) at minimum 2-year follow up.

Methods

A prospective analysis was conducted on 10 patients (8 female) undergoing rTHA with custom 3D-printed titanium implants (3D-TTi), manufactured via laser sintering from Ti6Al4V titanium powder. At 1-year follow-up were measured the angles of inclination and anteversion, the vertical (VCOR) and horizontal (HCOR) center of rotation, and leg length difference (LLD). The Harris hip score (HHS) and Oxford hip score (OHS) was used. The mean follow-up period was of 36.4 (range 24.5–48.2) months, ensuring a maximum follow-up at 4 years.

Results

All custom 3D-TTi (100%) in patients were positioned within the Lewinnek safe zone:. The COR was restored in all patients after rTHA. HCOR did not differ from the contralateral limb before and after rTHA. The VCOR was different before surgery, and after rTHA it did not differ due to correction by -6.9 mm. In 9 of 10 patients, the correction of the length of the operated limb did not exceed 4 cm, and the mean LLD after rTHA was 6.3 mm. One patient had a dislocation at 3 weeks. At 1-year follow-up, HHS (24.0±11.4 vs. 93.3±1.6) and OHS (8.1±2.6 vs. 41.3±4.1) were significantly improved (p=0.005).

Conclusion

At a minimum follow-up of 2 years, none of the 3D-printed trabecular titanium implants required revision, indicating promising early implant stability and function in patients with severe acetabular defects.

Keywords

custom 3D-printed porous titanium implants acetabular titanium implants revision hip replacement bone defect center of rotation

Brief introduction

In acetabular reconstruction during revision total hip arthroplasty (rTHA), oversized cups are often utilized to address bone loss.¹ However, severe defects may preclude the use of jumbo cups due to inadequate initial stability or insufficient bone-implant integration.² For a majority of Paprosky type II and type III acetabular defects, techniques including rings, cages, impaction grafting, allografts, cup-cages, and augments are employed.¹ Though initial stability can be achieved with rings and cages, multiple studies have demonstrated unsatisfactory long-term implant survival. Furthermore, bone grafting is restricted by graft availability and risks like disease transmission and resorption over time.³ Cup-cages have applications in major discontinuity defects.⁴ Thanks to favorable osteointegrative properties, recent data on 3D-printed porous titanium augments and cups has shown promising early and mid-term outcomes.^5,6 Standard off-the-shelf 3D-printed augments and cups offer excellent bone ingrowth potential in a more accessible and affordable package.^7–10 Both customised and standardized 3D-printed implants may have utility in addressing acetabular bone loss, they have a three-dimensional highly porous trabecular structure, a high coefficient of friction and biocompatibility that facilitate their rapid and complete osseointegration.^5,11 This quality is important in rTHA, where achieving stable and durable fixation in the setting of bone loss is crucial. However, the advantage of 3D-printed acetabular implants over conventional implants with respect to functional outcomes in patients has not yet been proven.¹² There is also insufficient evidence to support the advantage of tantalum implants over titanium implants for the prevention of periprosthetic infection.^13,14 Ayers et al.¹⁵ in a randomised controlled trial showed no difference in proximal migration when comparing tantalum and titanium acetabular cups over 5 years of follow-up.

Custom 3D-printed trabecular titanium implants (3D-TTi) components can minimise interfacial stresses and better restore native anatomy, but have disadvantages like high cost and long production time, making them most appropriate for extreme defects requiring extensive exposure.^16–19 The ability to customise these components based on digital 3D reconstructed pelvic models from CT data to fit the unique anatomical and defect characteristics of each patient may help to reduce the risk of dislocation and aseptic loosening during rTHA. Preoperative planning and intraoperative monitoring can minimise nerve tension and reduce the potential risk of neurovascular injury associated with surgical lower limb lengthening.

There are currently not enough studies with a high level of evidence for custom acetabular 3D-TTi, as opposed to standard 3D-TTi.^5,11 In a systematic review on the use of custom acetabular 3D-TTi, all 18 articles had level IV evidence,¹¹ whereas in a systematic review on standard 3D-TTi, 11 of 12 articles had level III evidence [5]. Although both reviews showed a high survival rate for 3D-TTi (custom 94% vs. standardised 95.5% with a mean follow-up of 4.9 and 3.8 years), the infection rate for custom acetabular 3D-TTi seems to be higher than for standardized (11.5% vs. 2.8%), and data on instability and migration of custom 3D-TTi are scarce.^5,11 A limitation for data interpretation may be that in a systematic review of standardised 3D-TTi, 7 out of 12 articles used the Delta TT system (Limo Corporate, San Daniele, Italy) [5], which necessitates the analysis of other standardized 3D-TTi. In general, standardised 3D-TTi facilitate the integration of the implant with the existing bone, providing a stable base for the new prosthesis and they can be used in most Paprosky type II and III acetabular defects without pelvic rupture.²⁰ Whereas custom-made 3D-TTi are suitable for these and more complex cases.²¹

This study aims to evaluate the clinical and radiographic outcomes of custom 3D-printed trabecular titanium implants for acetabular rTHA in patients with severe acetabular defects at minimum 2-year follow up.

Materials and methods

Patients

Prospective study included 10 patients (10 hips) older 50 years (mean age 62.9; range 54–71), 8 (80%) female (Table 1). Patients were included in study if they had all criteria’s: aseptic instability with/or not dislocation of acetabular component with acetabular bone sclerosis and osteoporosis, severe acetabular bone defect (Paprosky type 2 or 3). Criteria’s for excluded were infection in surgical site for rTHA, active tuberculosis, lungs chronic diseases, cardiovascular diseases, severe renal and hepatic diseases, thrombophlebitis and thromboembolism, strokes and convulsive syndromes, severe diabetes mellitus.

Table 1.

Demographic characteristics and clinical data.

Case number	Gender	Age (years)	BMI (kg/m²)	Primary diagnosis	Previous revisions	Reason for revision	Paprosky classification	Follow-up (months)
1	F	65	26.8	PIC		AI	II	36.5
2	F	55	24.1	PIC	1	O	II	33.3
3	F	71	25.7	PIC		AI	II	24.5
4	M	65	18.8	PIC		AI	II	43.4
5	F	60	24.1	DC		AI	II	42.5
6	M	59	23.2	DC		AI	II	36.8
7	F	54	26.4	DC		O	III	48.2
8	F	71	24.3	DC	1	AIAP	III	28.6
9	F	68	24.3	PIC		O	III	36.4
10	F	61	25.5	DC	1	AI	III	33.7

F – female, M – male, PIC – primary idiopathic hip osteoarthritis, DC – dysplastic coxarthrosis, AI – aseptic instability, O – osteolysis, AIAP – aseptic instability with acetabular protrusion.

For all patients performed cementless rTHA with custom 3D-TTi between March, 2021, and December, 2023 at single center by one surgeon with experience more than 25 years. The indications for rTHA were aseptic instability (6 hips), osteolysis (3 hips) and aseptic instability with acetabular protrusion (1 hip) (Table 1). Three patients (30%) already had previous rTHA. The mean follow-up period was of 36.4 (range 24.5–48.2) months, ensuring a maximum follow-up at 4 years. None of the patients were lost to follow-up.

All patients included in the study signed informed consent. The study materials were reviewed and approved by the Local Bioethics Committee (Protocol No. 191 from 22.04.2019; No. 229 from 20.02.2023) in accordance with the World Medical Association Declaration of Helsinki.

Preoperative planning

Preoperatively 3D structure information of acetabular bone deficiencies was obtained by computed tomography (CT) in CT scanners (64 or 128 slice with thickness 1.0-1.5 mm). For some patients was performed 2500 to 3500 slices according to pelvic size. An analysis of preoperative anteroposterior X-rays was performed according to the Paprosky’s classification system for acetabular bone deficiencies by two surgeons to assess the extent of bone loss and the feasibility of achieving cementless fixation based on specific bone loss patterns.²²

Custom 3D-TTi were designed and preoperative planning was performed by two engineers together with surgeons according to the X-rays and 3D CT data. Following by 3D pelvis model was designed and printed in 3D printer (Additive laser technology of Ukraine LLC, Dnipro, Ukraine) using Solidworks software (SolidWorks 2019 SP 1.0, Dassault Systèmes, USA). Then, surgeons performed simulated surgery on the 3D pelvis model, and made the preliminary decisions of prosthesis selection, prosthesis sizing and the position of augmentation. The custom 3D-TTi were manufactured with electron beam melting technology from Ti-6Al−4V titanium powder (LPW Technology Ltd T/A, Widnes, United Kingdom) and were composed of titanium particles melted layer by layer with a three-dimensional mesh structure (Figure 1). The surrounding temperature inside the 3D printer is 1,000°C, with the electron beam raising the temperature slightly to around 1,200°C to melt the material, which means smaller thermal gradients are generated and the component experiences less residual stress. The pore size (350-400 μm) and porosity (80%) to promote cancellous bone growth were determined with computer-aided design.

Surgical technique

Preoperatively and intraoperatively, appropriate strategies were used to continuously assess for the presence of pelvic discontinuity, as both discontinuity and acetabular loss represent significant risks in rTHA scenarios.

The conventional posterolateral approach was utilized for exposure. Extended trochanteric osteotomies were never performed to improve visualization; only soft tissue releases were used. Following removal of the previous implants and acetabular debridement, synovial fluid and deep tissue samples were collected from all patients for laboratory microbiological testing to determine further appropriate postoperative antibiotic therapy. Any fibrous tissue that may interfere with osseointegration was also removed. To ensure a close contact between the native bone and custom 3D-TTi on it, a careful and step-by-step reaming of the acetabular defect was performed, starting from a smaller size and up to a diameter that was 1-2 mm smaller than the size of the custom 3D-TTi. After the rimming of the acetabulum and before the placement of the custom 3D-TTi, a plastic 3D-printed model of the implant was always used to check the correct positioning. In achieve the desired inclination and anteversion angles, reaming was done from the smaller size to a size 1-2 mm smaller than the custom 3D-TTi. After reaming, any residual bone particles were meticulously cleaned and the area was thoroughly irrigated. To address any remaining gaps, morsellized bone allograft was employed. Subsequently, the trial 3D-printed plastic cup was inserted again for assessment and its positioning verified. If the positioning, stability, and the area of contact between the custom 3D-TTi and the host bone were deemed satisfactory, the interface was verified through intraoperative fluoroscopy.

Then the custom 3D-TTi was securely secured and pressed into place using a suitable press-fit technique and additional screws for reinforcement. Prior to screw fixation, component position and stability were confirmed by intraoperative X-ray fluoroscopy when possible and according to the preoperative plan. To achieve robust fixation and promote osseintegration in cases of acetabular insufficiency, the custom 3D-TTi was oriented with a slight upward tilt, targeting an inclination angle of 45° to 50°, while maintaining neutral anteversion of 0° to 5°, according to recommendations. The precise positioning of the custom 3D-TTi may necessitate modifications to optimize bone contact and facilitate ingrowth, taking into account the unique size and shape of the defect. The custom 3D-TTi was then positioned within the acetabular defect and secured to the pelvic bone using 6.5-mm screws. The use of a drill guide for locking screw placement provides a controlled range of angulation options. As longer as possible screws were used, directed posterosuperiorly towards the sciatic notch or anteroinferiorly towards the pubis. A thorough understanding of the pertinent anatomical structures is essential for surgeons to safely predrill holes, minimizing the risk of inadvertent damage to surrounding neurovascular structures, particularly the anteriorly situated obturator artery. Additional screw fixation was used for large Paprosky type 3 defects exhibiting suboptimal initial fixation using additional holes in the titanium implant. Polyethylene liner Longevity® Highly Crosslinked Polyethylene (Zimmer Biomet, Warsaw, Indiana, USA) was used with BIOLOX® delta Option Ceramic Femoral Head System (Aesculap, Implant Systems, Inc., USA). Only uncemented liners were used into custom 3D-TTi. The polyethylene liner was fixed using an integrated mechanical locking mechanism (snap-fit or conical-fit), as provided in the implant design, ensuring primary stability and minimizing micromotion at the metal–polyethylene interface. Trial reductions enabled assessment of joint biomechanics before wound closure.

Postoperative assessment

Patients were generally advised to use crutches for mobility, with partial weight-bearing being introduced from the first day after rTHA. Transition to a full weight-bearing status was encouraged following a clinical and X-rays evaluation from 1.5 to 2 months after surgery. Patients underwent assessments at one-year follow up and then annually, if possible (Table 1). To monitor progress and healing, standard anteroposterior (AP) and lateral radiographs were taken three days after surgery and subsequently during each follow-up visit. Radiological evaluation was centered on determining the overall survival of the procedure, defined by the absence of any need for additional revisions to the acetabular component.

The angles of inclination and anteversion of the custom 3D-TTi were quantified using the AP radiographs at one-year follow up, following the methodology outlined by Bachhal et al.²³ for 3D-TTi orientation. According to these data, position of the custom 3D-TTi was evaluated according to the Lewinneck safety zone criteria.²⁴

The vertical (VCOR) and horizontal (HCOR) center of rotation, and leg length difference (LLD) were measured preoperatively and at one-year follow up by two observers. The VCOR was defined as the vertical distance from the line connecting the centers of the femoral heads to the transeschial line. The HCOR was defined as the horizontal distance measured from the center of the femoral head to a medial landmark such as the teardrop. The LLD was quantified by measuring the differential distance from the base of the teardrop to the tip of the corresponding lesser trochanter^25,26 (Figure 2). To assess the level of asymmetry between the operated and contralateral sides, both pre- and postoperatively for each individual patient, the absolute values of the differences in VCOR and HCOR were calculated for the right and left hip, respectively:

Δ VCOR = contralateral VCOR - operated VCOR

Δ HCOR = contralateral HCOR - operated HCOR

For assessing the ingrowth of uncemented acetabular components, the criteria set forth by Moore et al. were utilized.²⁷

The stability of custom 3D-TTi was evaluated according to additional criteria: radiographic failure included migration of the component by more than 3 mm in either horizontal or vertical direction, the presence of radiolucent lines wider than 2 mm in all DeLee and Charnley zones, screw fractures, or a variation in the cup angle exceeding 5°.²⁸ Progressive radiolucent lines (RLLs) were scrutinized in radiographic evaluations at 3, 6, 12 months during the first postoperative year, and then annually after that.²⁸

The clinical assessment of patients was conducted using the Harris hip score (HHS)²⁹ and Oxford hip score (OHS) (using 0-48 scale) at one-year follow up.³⁰

Statistical analysis

The mean values and ranges were calculated for demographic data. Categorical variable values are presented as percentages. Shapiro-Wilk was used for to analyze of distribution. Quantitative X-ray and clinical assessments are given as the mean and standard deviation (SD) or 95% confidence interval [CI]. Scatter-plot were constructed to compare pre- and postoperative values. The effect size was estimated by changes in preoperative and postoperative (12 months after rTHA) difference between positions of the center of rotation (COR) for both hips and LLD. The Wilcoxon signed-rank test far related samples was used to determine the difference between pre- and postoperative values. Differences was statistically significance if p < 0.05.

Results

Patients

90% (9) patients in study had normal body mass with the mean body mass index (BMI) 24.3 kg/m² (range 18.8–26.8 kg/m²). Only patient #4 has lower BMI caused by post-COVID-19 syndrome. Detailed demographic characteristics of patients showed in Table 1.

According to preoperatively anteroposterior radiographs, all patients were found to have severe acetabulum deficiencies: 60% Paprosky type II (6 patients,) 40% Paprosky type III (4 patients) (Table 1).

X-ray assessment

To assess the prospect of achieving optimal joint mechanics, minimizing the risk of dislocation or premature wear we assured that angulation and anteversion were proper. At one-year follow up the mean cup inclination angle was 42.3°±4.4° (range 35°–50°) and the mean anteversion angle was 13.4°±1.78° (range 10°–15°). All custom 3D-TTi (100%) in patients were positioned within the Lewinnek safe zone, where pairs of cup inclination and anteversion angle values (45°; 14°) and (40°; 15°) were observed twice each (Figure 3).

The VCOR and the HCOR values in Patient #10 were higher by 2 times compare to values in other patients, so these results describe separately.

In 9 patients, the pre-VCOR of the operated side was significantly lower from contralateral side: the pre-ΔVCOR was –8.4 mm (95% confidence interval [CI]:–13.8, 3.0; p=0.021). (Table 2). At one-year follow-up the VCOR of the operated and the contralateral sides was similar: the post-ΔVCOR was –1.5 mm (95% CI: –3.63, 0.69; р=0.138). We found tendency to decreased the VCOR at –6.9 mm (95% CI: –13.1, –0.8; p=0.050) of the operated side following rTHA compared to preoperatively values.

Table 2.

Clinical outcomes.

Case number	Incli-nation angle (degrees)	Ante-version angle (degrees)	VCOR (mm)			HCOR (mm)			LLD (mm)
			Preoper		Postoper	Preoper		Postoper	Preoper	Postoper
			Surgical side	Contr side	Surgical side	Surgical side	Contr side	Surgical side	Preoper	Postoper
1	35	15	17.3	9.6	14.7	10.5	39.2	25.5	-12.5	+15.5
2	40	10	17.1	7.6	14.5	9.7	31.3	31.6	-20.5	+2.5
3	38	12	23.1	10.2	11.7	19.4	23.2	30.1	-15.5	+2.0
4	45	14	34.3	18.1	17.5	12.1	34.2	36.1	-10.5	+5.0
5	45	15	34.1	19.7	18.5	38.8	26.5	29.4	-10.0	+5.5
6	40	15	27.5	12.5	11.8	30.6	27.4	30.1	-20.0	+5.5
7	40	15	14.1	17.2	18.6	39.7	31.3	34.4	-25.0	+5.5
8	45	12	17.2	15.8	17.3	13.1	25.7	28.5	-10.0	+10.5
9	45	14	15.6	14.1	13.4	10.1	28.1	30.7	-15.5	+5.0
10	50	12	67.1	26.1	47.9	49.6	31.1	42.4	-50.5	+10.0
Mean			22,26	13,87	15,33	20,44	29,66	30,71	-15,50	6,33
SD			7,91	4,18	2,73	12,53	4,90	3,12	5,36	4,19

Preoper – preoperative, Postoper – postoperative, Contr – contralateral, VCOR – vertical center of rotation, HCOR – horizontal centre of rotation, LLD – leg length discrepancy.

In Patient #10 the results was similar to other patients, the pre-VCOR of the operated side was 2.6 times higher compared to the contralateral side and decreased following rTHA compare to the pre-VCOR (Table 2).

Contrarily, the HCOR pre- and postoperatively of the both sides did not differ significantly: the pre-ΔHCOR was 9.2 mm (95% confidence interval [CI]: –2.1, 20.6; p=0.086), the post-ΔHCOR was –1.1 mm (95% CI: –5.5, 3.4; p=0.110). Following rTHA the HCOR of the operated side showed tendency to increase at 10.3 mm (95% CI: 0.8, 19.8; p = 0.051) compared to preoperatively values.

In Patient #10, the preoperatively HCOR was 1.6 times higher comparing with the contralateral side and decreased following rTHA (Table 2).

At one-year follow-up the LLD was significantly decreased: –21.8 mm (95% CI: –25.9, –17.7; p=0.008). Patient#10 also had correction of length of operated leg (Table 2).

Two patients (#6, #9) had RLLs in Zone III described by DeLee and Charnley at one-year follow up, but at subsequent annual evaluations no progression or new RLLs were detected.

Complications

Postoperatively none of the severe complications such as periprosthetic acetabular fractures, neurovascular damage, and deep vein thrombosis were recorded in the patients. There was no evidence of greater trochanter fracture and femoral shaft fracture. One patient #9 had a dislocation at 3 weeks treated open reduction to realign the dislocated hip followed by a ball size change to an XL to prevent re-dislocation. No further dislocations were reported during the follow-up period (Figure 4). One patient had wound discharge treated surgical debridement and the wound healed properly.

Functional outcomes

At one-year follow-up, HHS (24.0±11.4 (range 10–48) vs. 93.3±1.6 (range 91–95)) and OHS (8.1±2.6 (range 4–12) vs. 41.3±4.1 (range 35–46)) were significantly improved (p=0.005). All patients had HHS values that can be interpreted as excellent and according to OHS values all of them had satisfactory joint function following rTHA.

Discussion

In our study we showed midterm results of successful use of custom acetabular 3D-TTi in 10 patients over 50 years old with Paprosky type 2 or 3 defects for rTHA. COR was restored in all patients after rTHA, which contributed to the lengthening of the operated limb by an average of 21.8 mm. We found no difference in HCOR compared to the contralateral limb both before and after rTHA. Whereas VCOR of the operated limb was different before surgery and not after due to correction by -6.9 mm. Similar results for HCOR were obtained in two other studies using custom-made 3D-TTi for rTHA.^31,32 Also in three studies, the authors found a reduction in VCOR of the operated limb one year after rTHA using custom-made 3D-TTi.^6,31,32

Limb length correction has a positive effect on patients’ mobility and comfort, but lengthening the lower limb by more than 4 cm increases sciatic nerve tension and the risk of neurovascular injury. In our study, 9 of 10 patients had a correction of less than 4 cm, and the LLD after rTHA was 6.3 mm. This is larger than in two other similar studies where the LLD after rTHA was 3.4 mm and 4.6 mm,^21,31 but smaller than the Fu et al.¹⁷ 7.7 mm. This is probably due to the larger LLD before rTHA (-15.5 mm) in our patients as well as more severe defects compared to Zhang et al.³¹ At the same time, despite the smaller mean LLD value in Zhang et al.³¹ compared to ours, 6 out of 31 patients were severely limping after 1.8 years according to their results. The 10th patient had a lower limb shortening of 5.5 cm before revision surgery. At the revision intervention after mobilisation of the nerve and its isolation from the scar tissue, the limb length was restored with a slight increase of 1 cm without any neurological disorders at a follow-up of 33.7 months. Paralysis of the sciatic nerve occurred immediately and 4 weeks after rTHA in 1 case out of 35 patients in similar studies, which in both cases did not require a second operation and resolved within a month.^6,32 The absence of cases of sciatic nerve injury in our study confirms the correctness of surgical planning and performance of rTHA

Proper cup inclination and anteversion are important to prevent dislocation after THA. Although the concept of the “safe zone” exists to address this issue, adherence to it does not guarantee the absence of dislocation, indicating that individual anatomical and surgical factors must be taken into account. After one year of follow-up, all 9 patients had the cup inside the “safe zone”; only the 10th patient had values at the border of this zone. According to a systematic review, dislocation and periprosthetic infection is the main cause of re-operation when custom-made 3D-printed implants are used.¹¹ At the same time, such implants show a high survival rate of 94.0% for Paprosky type IIIA-IIIB defects and a mean follow-up of 4.9 years.¹¹ In three studies similar to ours, dislocation occurred in patients at 5 weeks,⁶ 6 weeks¹⁹ after rTHA and between stages of two-stage rTHA (18.3 weeks).²¹ In our study, dislocation occurred after 3 weeks in 1 out of 10 patients, which was successfully treated by open repositioning also as Burastero et al.,²¹ although other investigators applied closed repositioning.^6,19 We found no cases of periprosthetic infection during ≈3 years (mean 36.4 months) of follow-up, although according to a systematic review its incidence is 11.5% with custom 3D-TTi over 4.9 years.¹¹ Only one patient had a superficial postoperative wound infection, which was successfully treated by debridement.

Like other researchers,^{17,19,21,31,32} we found no cases of custom 3D-TTi migration with a minimum follow-up period of 2 years and a maximum of 4 years. This is also consistent with the results of a systematic review for custom 3D-TTi, according to which their migration rate is quite low 0.3%.⁵ Fang et al.⁶ found one case (n=35) of cranial migration of custom 3D-TTi by 2 mm 4 weeks after rTHA, which disappeared after 3 months. In two patients after one year we detected RLLs in Zone III described by DeLee and Charnley, similar RLL placement was detected by Huang et al. in 1 of 32 patients, and in two others in Zone 1 and 2.¹⁸ Importanly, in our cohort no progression or new RLLs were detected at subsequent annual evaluations up to mean follow-up of 36.4 months (range 24.5-48.2). These findings indicate that the presence of early RLLs did not compromise the future stability and osseointegration of custom 3D-TTi.

In our study one year after rTHA, the Harris Hip Score was greater than 90 points in all 10 patients, corresponding to excellent functional results. This is consistent with similar clinical studies where the mean Harris Hip Score was between 69.2 and 88.4 after rTHA,^{6,17,19,21,31,32} and with the results of a systematic review (mean 86.7).¹¹ In the longest follow-up, 7 years after 3D-TTi Huang et al. obtained a Harris Hip Score of 97 ¹⁸. We obtained similar scores (41.3±4.1) on the Oxford scale as Kong et al. (38.8±1.7)¹⁹ and Burastero et al. (39.6 ± 3.6),²¹ which show the success of treating patients after one year of follow-up.

Our study has several limitations. It was a single-centre study with a small sample without a control group, but with a minimum 2-year follow-up and a prospective design. Also different methods of defect reconstruction were used in patients because of their individual characteristics. This demonstrates the complexity of rTHA in severe acetabular defects and the importance of choosing an appropriate fixation method to ensure implant stability while minimising potential adverse effects. Further multicentre controlled studies of longer duration on the use of custom 3D implants in patients with severe acetabular defects are needed.

Conclusion

The use of 3D-printed trabecular titanium implants for acetabular revision total hip arthroplasty in patients with severe acetabular defects (Paprosky type 2 or 3) resulted in excellent functional outcomes based on the Harris Hip Score and Oxford Hip Score. At a minimum follow-up of 2 years, none of the acetabular components required revision, indicating promising early implant stability and function.

Footnotes

ORCID iD

Valentyna Maltseva

Ethical considerations

Approval was obtained from the Bioethics Committee of Sytenko Institute of Spine and Joint Pathology National Academy of Medical Sciences of Ukraine, Kharkiv, Ukraine (protocol number 191 from 22.04.2019; number 229 from 20.02.2023) in accordance with the World Medical Association Declaration of Helsinki.

Consent to participate

All patients included in the study signed informed consent.

Author contributions

Conception and design: SB and VsMk; Data collection: VsMk, SB; Assembly of data: SB, VsMk, OP, SvBr; Creation of implants: OP and SvBr. Statistical analysis performed by VM. The first draft of the manuscript was written by VsMk, SvBr. The review and editing was performed by SB and VM. All authors read and approved the final manuscript.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

Declaration of conflicting interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Data Availability Statement

All data generated or analysed during this study are included in this published article.*

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